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Author
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Topic: Is the Piston on the Way Up or Down?
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68 S-code GT
Gearhead Posts: 993
From: Sayreville, NJ, US
Registered: Mar 2000
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posted 03-10-2002 11:24 AM
   
While changing the umbrella seals on a 289, I dropped the No. 3 exhaust valve.  The rotor is between the No. 1 and No. 5, is the No. 3 piston on the way up or down? I figured that since it is still in the valve guide and I might be able to turn the crank by hand forwards or backwards. I don��t want to have to remove the head if I don��t have to!
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V8 Thumper
Gearhead Posts: 3267
From: Orange, Ca. United States of America
Registered: Dec 2001
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posted 03-10-2002 12:51 PM
DO NOT TAKE THIS AS ABSOLUTE FACT... but I'd say #3 is on its way back down. I wouldn't move the crank at all while that valve is cocked in there, you will bend the valve.
How about a magnet? Try using a shop vac to suck the valve back up again? Or even the wife's house vac, provided its got an accessory hose, just seal the hose around the guide boss the best you can, you might get lucky.Once you fish that thing out, here's my little trick. Note: Piston must be at TDC. Take the needle valve out of the end of a compression tester, thread it into the spark plug hole. Hook an air hose to the tester, pressurize the cylinder. Valves stay up (seated), provided no one un-plugs your air compressor  I've also heard of guys threading nylon rope onto the spark plug hole while the piston is 1/2 way up, turn the motor over by hand until it's at TDC, squishing the rope against the combustion chamber to do what you've gotta do. One more thing...
Good luck  [This message has been edited by V8 Thumper (edited 03-10-2002).]
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SuperDave
Gearhead Posts: 123
From: Tacoma, WA USA
Registered: Jun 2000
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posted 03-10-2002 01:14 PM
Stuffing nylon rope into the cylinder then rotating the engine slowly by hand is an "old farmer" trick that works well for me! If you fill the cylinder with rope, the valve can't fall farther and it will be pushed up when the piston rises.
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DidgeyTrucker
Gearhead Posts: 970
From: Greenbrier, TN USA
Registered: Oct 99
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posted 03-10-2002 10:35 PM
Two pistons reach top dead center at the same time. One is on the end of the compression stroke and the other is the end of the exhaust stroke.
In the Ford firing order - 15426378 - #5 and #3 are both approaching TDC if the rotor is between #1 and #5. 1542
6378 The plug is about to fire on #5 and the exhaust valve is about to open on #3. Tracy
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68 S-code GT
Gearhead Posts: 993
From: Sayreville, NJ, US
Registered: Mar 2000
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posted 03-11-2002 07:36 AM
I didn't get lucky with the shop vac. I'll have to get the a big magnet from my dad. If that don't work I'll go with the rope! quote:
Originally posted by V8 Thumper:
How about a magnet? Try using a shop vac to suck the valve back up again? Or even the wife's house vac, provided its got an accessory hose, just seal the hose around the guide boss the best you can, you might get lucky.Take the needle valve out of the end of a compression tester, thread it into the spark plug hole. Hook an air hose to the tester, pressurize the cylinder. Valves stay up (seated), provided no one un-plugs your air compressor I've also heard of guys threading nylon rope onto the spark plug hole while the piston is 1/2 way up, turn the motor over by hand until it's at TDC, squishing the rope against the combustion chamber to do what you've gotta do. One more thing...
Good luck [This message has been edited by V8 Thumper (edited 03-10-2002).]
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68 S-code GT
Gearhead Posts: 993
From: Sayreville, NJ, US
Registered: Mar 2000
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posted 03-11-2002 07:41 AM
If the #3 is approaching TDC, how could the valve drop so much?  quote:
Originally posted by DidgeyTrucker:
Two pistons reach top dead center at the same time. One is on the end of the compression stroke and the other is the end of the exhaust stroke.
In the Ford firing order - 15426378 - #5 and #3 are both approaching TDC if the rotor is between #1 and #5. 1542
6378 The plug is about to fire on #5 and the exhaust valve is about to open on #3. Tracy
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V8 Thumper
Gearhead Posts: 3267
From: Orange, Ca. United States of America
Registered: Dec 2001
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posted 03-11-2002 10:33 AM
quote:
Originally posted by 68 S-code GT:
I didn't get lucky with the shop vac. I'll have to get the a big magnet from my dad. If that don't work I'll go with the rope!
Since the valve is already contacting the piston, the 'rope' won't do you any good. Try a small magnet... like the little telescoping type used to pick up nuts/screws from hard to reach spots, something narrow enough to send down the guide to grab the valve stem to draw it back up. If that dosen't work, you're probably looking at pulling the head. Sucks, I know, but rotating the crank with the valve bound against the piston will almost certainly bend the valve stem, which will almost certainly break once you try to start the motor. Then, you're looking at a shattered piston, metal shards in the oil, maybe break a rod...
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RonnieT
Gearhead Posts: 540
From: Port Allen, La. 70767
Registered: Jun 99
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posted 03-11-2002 09:41 PM
Well if you have a good set of stainless steel valves you can waste a day and get no where. Stainless steel is non-magnetic.------------------
Ronnie
69 mach1 351W-4V
70 Torino GT 351C-4v with a "shaker"
Mustangs and More Member #23
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Gary
Gearhead Posts: 725
From: Sarasota, Fla. USA
Registered: Jun 99
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posted 03-11-2002 10:12 PM
Have a spare valve laying around? Iv'e put oil down the guide and inserted a valve upside down until the stem tip just about touches the top of the stem of your dropped valve. It may take a few attempts but pull the valve out fairly quick and the dropped valve should follow it up. The oil and tight fit of the valve will make a good enough seal to suck the valve back up, be quick to grab it as it may fall back down. Took me three or four times trying it but it worked for me...Good luck 
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68 S-code GT
Gearhead Posts: 993
From: Sayreville, NJ, US
Registered: Mar 2000
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posted 03-11-2002 10:30 PM
Well the magnet didn��t work either! It really was a strong one too! If a 351w valve stem is the same then I'll try your game along with a couple Ours Henry's quote:
Originally posted by Gary:
Have a spare valve laying around? Iv'e put oil down the guide and inserted a valve upside down until the stem tip just about touches the top of the stem of your dropped valve. It may take a few attempts but pull the valve out fairly quick and the dropped valve should follow it up. The oil and tight fit of the valve will make a good enough seal to suck the valve back up, be quick to grab it as it may fall back down. Took me three or four times trying it but it worked for me...Good luck
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SuperDave
Gearhead Posts: 123
From: Tacoma, WA USA
Registered: Jun 2000
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posted 03-11-2002 10:46 PM
Using the "rope trick" I coulda had this baby back on the road by now. What could be simpler?
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68 S-code GT
Gearhead Posts: 993
From: Sayreville, NJ, US
Registered: Mar 2000
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posted 03-11-2002 10:54 PM
Will the rope work if the valve is up against the piston? I really don��t know if it is or isn��t. I almost started tearing the top end of the engine off. quote:
Originally posted by SuperDave:
Using the "rope trick" I coulda had this baby back on the road by now. What could be simpler?
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steve'66
Gearhead Posts: 6150
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 03-11-2002 11:56 PM
I'd pull the head, head gaskets are cheap and you get to see how the pistons and bores look while you're at it. SteveW
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68 S-code GT
Gearhead Posts: 993
From: Sayreville, NJ, US
Registered: Mar 2000
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posted 03-12-2002 07:14 AM
That��s what I was thinking, plus I want to install the 4V setup I have! The engine is supposed to have 30k on it with a 302 crank. I guess this will be my opportunity to check it out. quote:
Originally posted by steve'66:
I'd pull the head, head gaskets are cheap and you get to see how the pistons and bores look while you're at it. SteveW
[This message has been edited by 68 S-code GT (edited 03-12-2002).]
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68 S-code GT
Gearhead Posts: 993
From: Sayreville, NJ, US
Registered: Mar 2000
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posted 03-13-2002 08:00 AM
The heads will come off this weekend!This is one of the reasons why on all of the rebuilds I use Teflon seals.
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